package 反射5;

import java.lang.reflect.Field;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;

/**
 * @Auther:lele
 * @Date:2025/3/13
 */
public class MyJbutils {


    public static <T> List<T> findList(String sql, Class<T> c) throws Exception {
//        创建集合，存储对象
        ArrayList<T> arrayList = new ArrayList<>();
        //注册驱动
        Class.forName("com.mysql.cj.jdbc.Driver");
        //获取链接
        Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/ma?useSSL=false&serverTimezone=UTC", "root", "123456");
        //创建statement
        Statement statement = conn.createStatement();
        //返回结果集合
        ResultSet resultSet = statement.executeQuery(sql);
        System.out.println("resultSet = " + resultSet);
        ResultSetMetaData metaData = resultSet.getMetaData();


        //获取集合中列数
        int count = metaData.getColumnCount();
        System.out.println("count = " + count);
        //解析结果集合
        while (resultSet.next()) {
            //动态获取一行数据之后，封装成实体对象
            T t = c.newInstance();
            System.out.println("t = " + t);
            for (int i = 1; i <= count; i++) {
                //通过列的序号获取列值
                Object value = resultSet.getObject(i);
                if (value != null) {
                    //通过列的序号获取列名
                    String columnName = metaData.getColumnName(i);
                    System.out.println("columnName = " + columnName);
                    Field declaredField = c.getDeclaredField(columnName);
                    declaredField.setAccessible(true);//允许访问javabean私有属性
                    declaredField.set(t, value);
                }
            }
            arrayList.add(t);


        }
        return arrayList;
    }
}
